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Qual foi o problema usado para resolver? É o módulo do Apache ou algo mais?
Lingerd is a daemon (service) designed to take over the job of properly closing network connections from an http server like Apache.
Because of some technical complications in the way TCP/IP and HTTP work, each Apache process currently wastes a lot of time "lingering" on client connections, after the page has been generated and sent. Lingerd takes over this job, leaving the Apache process immediately free to handle a new connection. As a result, Lingerd makes it possible to serve the same load using considerably fewer Apache processes. This translates into a reduced load on the server.
Lingerd is particularily useful in Apache webservers that generate dynamic pages (e.g in conjunction with mod_perl, mod_php or Java/Jakarta/Tomcat).
More importantely, lingerd can only do an effective job if HTTP Keep-Alives are turned off; since keep-alives are useful for images, the recommended lingerd setup is to have an Apache/mod_whatever/lingerd server for the dynamic pages, and a plain Apache (or thttpd or boa) for the images.
Fonte O QUE É LINGERD?